﻿// Copyright 2004-2011 Castle Project - http://www.castleproject.org/
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#region 导入名称空间

using System;
using System.Diagnostics;
using System.Reflection.Emit;

#endregion

namespace LightWork.DynamicProxy.Generators.Emitters.SimpleAST
{
    [DebuggerDisplay("argument {Type}")]
    public class ArgumentReference : TypeReference
    {
        public ArgumentReference(Type argumentType)
            : base(argumentType)
        {
            Position = -1;
        }

        public ArgumentReference(Type argumentType, int position)
            : base(argumentType)
        {
            Position = position;
        }

        internal int Position { get; set; }

        public override void LoadAddressOfReference(ILGenerator gen)
        {
            throw new NotSupportedException();
        }

        public override void LoadReference(ILGenerator gen)
        {
            if (Position == -1)
                throw new ProxyGenerationException("ArgumentReference unitialized");
            switch (Position)
            {
                case 0:
                    gen.Emit(OpCodes.Ldarg_0);
                    break;
                case 1:
                    gen.Emit(OpCodes.Ldarg_1);
                    break;
                case 2:
                    gen.Emit(OpCodes.Ldarg_2);
                    break;
                case 3:
                    gen.Emit(OpCodes.Ldarg_3);
                    break;
                default:
                    gen.Emit(OpCodes.Ldarg_S, Position);
                    break;
            }
        }

        public override void StoreReference(ILGenerator gen)
        {
            if (Position == -1)
                throw new ProxyGenerationException("ArgumentReference unitialized");
            gen.Emit(OpCodes.Starg, Position);
        }
    }
}